A collision with an obstacle in the surrounding environments may occur when a robot arm which handle things or the like is operated. In order to stably operate the robot arm even after the collision, it is necessary to detect a collision of the robot arm.
In this regard, a technique has been proposed which estimates an external torque generated by the effect of disturbance caused by a collision of the robot arm and the like and thus determines that the leading end of the robot collides on the basis of the external torque being equal to or greater than a predetermined threshold without using force sensors.
However, due to the effect of a modeling error in the dynamic model of the robot arm, an error is included in the external torque. Therefore, it is difficult to detect the disturbance exerted on the robot arm with high precision.